What are retention services in clinical trials? 

Executive Summary 

Retention services in clinical trials are structured activities designed to help patients stay enrolled and complete the study as planned. They address common barriers to participation – such as logistical, emotional, or informational challenges – and aim to maintain motivation, engagement, and a positive patient experience. 

Retention services can include flexible scheduling, transportation support, ongoing communication, digital engagement tools, and personal assistance. They are typically provided by site teams, Site Management Organizations (SMOs), or specialized vendors. 

When choosing an SMO partner, Sponsors and CROs should carefully assess its retention capabilities – including experience with diverse populations, cultural sensitivity, readiness to support Decentralised Clinical Trials (DCTs), and the ability to proactively monitor retention indicators. Strong SMO support in this area is key to ensuring data quality, study timelines, and regulatory compliance. 

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Main objective of retention services in clinical trials

Recruitment is only the first hurdle in running a successful clinical trial. An equally demanding challenge begins once patients are enrolled: keeping them engaged until the study is completed. High dropout rates can significantly compromise a trial’s outcomes – leading to extended timelines, increased costs, or even inconclusive results. Recent studies indicate that dropout rates in clinical trials can range from 15% to 40%, depending on various factors such as trial duration and complexity^1,7,9. 

This is why retention services in clinical trials are now considered a critical success factor in clinical trial management. In this article, we explain what retention services are, why they are more important than ever – especially in Decentralized Clinical Trials (DCTs) – and what Pharma and CRO partners should expect from an SMO offering these services. 

Why patient retention is critical? 

Patient dropout is a well-known challenge in clinical trials. Various studies estimate that approximately 30% of study participants discontinue participation⁶. The consequences can be serious: 

• Delays in reaching recruitment targets and endpoints 

• Increased costs due to replacement recruitment 

• Data inconsistency due to missing observations 

• Ethical concerns, if patients disengage without proper support 

Patient retention is not just about keeping numbers up. It is about safeguarding: 

• Scientific validity of the trial 

• Regulatory compliance 

• Participant well-being and satisfaction 

Retention services are designed to address these points – proactively and continuously. 

What are retention services? 

Retention services encompass a set of activities and support mechanisms aimed at helping patients complete the clinical trial as planned. These services may be provided directly by the study site staff, by a Site Management Organization (SMO) partner working with the site, or through vendors specializing in specific patient support solutions. In trials supported by SMOs, it typically coordinates retention efforts in close collaboration with the site’s Principal Investigator and clinical team, ensuring consistency and compliance with the protocol and regulatory standards. 

Key objectives of retention services in clinical trials 

1. Reducing barriers to participation 

Patients often face practical, emotional, and logistical challenges that may discourage ongoing participation. Typical barriers include: 

• Transportation difficulties to attend visits 

• Work or family commitments that conflict with trial schedules 

• Financial burden  

• Complex or invasive study procedures that deter continued involvement 

• Lack of understanding of the trial’s purpose and value 

Retention services aim to mitigate these obstacles through flexible scheduling, logistical support, clear communication, and practical assistance². 

2. Maintaining motivation and engagement 

Patient engagement refers to maintaining an active, positive connection between the participant and the study. This includes: 

• Helping patients feel valued and informed about their contribution to science 

• Providing regular feedback (where allowed) on trial progress 

• Building a relationship of trust between patients and site/SMO staff 

• Offering appropriate emotional and psychological support throughout the study 

Engaged patients are more likely to adhere to study protocols and complete the trial, leading to more reliable data and outcomes.  

3. Improving the overall patient experience 

Experience includes how patients perceive their entire journey through the clinical trial, including: 

• The friendliness and professionalism of the site staff or SMO team 

• The convenience and clarity of the trial procedures 

• The respect shown for patient time and commitments 

• The sense of being part of an important effort, rather than feeling like a “data point” 

A positive patient experience directly correlates with higher retention rates. 

“The key is maintaining a close relationship with patients, so they feel comfortable and motivated to participate in a clinical trial. It’s a matter of trust. The investigator’s engagement is essential – patients need to feel appreciated.”  – Medicover MICS Principal Investigator responsible for recruitment in global Lupus studies, enrolling the highest number of patients worldwide. Read more.  

Typical retention services and responsibilities 

1. Communication & Engagement 

Responsibility for communication in retention services in clinical trials is typically shared between: 

• The site team, especially the study coordinators and Principal Investigator, who maintain direct patient contact 

• The SMO, which can provide structured communication plans, templates, and in some cases a dedicated patient liaison team that manages ongoing non-medical contact 

• External vendors, in some models, may be engaged for digital patient engagement tools 

Good communication practices include: 

• Personalized visit reminders through preferred patient channels (SMS, phone calls, email) 

• Educational materials that explain the study’s value and motivate continued participation 

• Patient newsletters to foster a sense of community and purpose 

• Access to a patient support line or helpdesk for addressing questions and concerns quickly 

Effective communication strategies are crucial in maintaining patient engagement and ensuring protocol adherence. 

2. Practical Support 

• Transportation assistance  

• Childcare support during visits (where appropriate) 

• Home health visits or remote monitoring (especially in DCTs) 

• Flexible visit scheduling, including evening/weekend options 

3. Personalised Approach 

• Building a trusted relationship between site staff / SMO coordinators and patients 

• Recognising and addressing individual patient needs (cultural, emotional, practical) 

• Providing approved incentives where allowed (e.g. reimbursement of time and expenses) 

4. Digital Retention Tools 

• Mobile apps for appointment reminders and study information 

• ePRO (electronic patient-reported outcomes) systems 

• Wearable devices for continuous engagement and monitoring 

The role of retention services in Decentralised Clinical Trials (DCTs) 

Retention becomes even more critical and complex in Decentralised Clinical Trials. Why? DCTs often reduce the number of in-person site visits, relying more on home-based data collection and digital interactions. This flexibility offers advantages but can also risk a loss of connection between the study team and patients. 

In DCT settings, SMO partners can add unique value by: 

• Providing trained staff for home nursing visits 

• Managing hybrid models where patients alternate between site and remote contacts 

• Offering 24/7 support through digital platforms 

• Ensuring compliance with data collection requirements in a remote context 

• Keeping patients motivated and engaged when face-to-face interaction is limited 

Without strong retention strategies, DCTs risk higher dropout due to lack of personal connection and support⁷. 

What should you expect from an SMO partner regarding patient retention? 

When selecting an SMO, Pharma and Contract Research Organisation (CRO) leaders should evaluate their partner’s retention capabilities carefully. Look for SMOs that offer: 

• Dedicated patient retention teams (not just generic coordinators) 

• Experience with diverse populations and local engagement strategies 

• Cultural sensitivity and knowledge of country-specific regulations 

• Flexibility to support hybrid or fully decentralised trials 

• Proactive monitoring of retention indicators – not just reacting to problems after they occur 

• Clear communication plans with both patients and sites 

How to assess an SMO’s retention capabilities? 

When evaluating potential SMO partners, Sponsors and CROs should ask specific questions to understand the SMO’s real-world approach to patient retention. Useful questions include: 

• Experience & Results 

• What has been your retention rate in recent trials in our target indication? 

• Can you share anonymised case examples demonstrating effective retention strategies? 

• Capabilities & Processes 

• Do you have a dedicated patient retention or patient engagement team? 

• How do you train site coordinators on retention best practices? 

• What digital tools do you offer to support retention? 

• DCT Readiness 

• How do you manage retention in hybrid or fully decentralised trials? 

• What support can you provide for home visits and remote monitoring? 

• Compliance & Ethics 

• How do you ensure communication and incentives comply with local and international regulations? 

• How is patient feedback gathered and incorporated into continuous improvement? 

Sponsors should also request: 

• References from past clients specifically regarding retention outcomes 

• Clear examples of patient-facing materials used in retention (subject to approvals) 

Conclusion 

Retention services in clinical trials are no longer an optional “add-on” – they are now a core component of high-quality clinical trial delivery. As trial designs evolve, especially with the growth of Decentralised Clinical Trials, patient-centric support and engagement become even more essential. 

When selecting an SMO partner, Sponsors and CROs should prioritise not only recruitment capabilities, but also robust and proactive retention services, ensuring that patients complete the journey they started. 

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Resources 

1. Strategies for participant retention in long term clinical trials: A participant –centric approaches, National Library of Medicine, accessed: 06.06.2025 

2. Redefining clinical trials: Adopting AI for speed, volume and diversity, IBM, accessed: 06.06.2025  

3. The Advent of Patient-Centric Technologies to Combat The High Dropout Rates: Revolutionizing Clinical Trials, Telehealth and  Medicine Today, https://telehealthandmedicinetoday.com/index.php/journal/article/view/474/1142 , accessed: 06.06.2025   

4. Enrollment and Retention: A Strategic Imperative for Clinical Trial Success, Confidence Pharmaceutical Research, accessed: 06.06.2025 

5. 2O24 Clinical Research Site Challenges Report, WCG, accessed: 06.06.2025 

6. Patient Recruitment in Clinical Trials: Areas of Challenges and Success, a Practical Aspect at the Private Research Site, Scientific research, https://www.scirp.org/journal/paperinformation?paperid=128354, accessed: 06.06.2025   

7. Unique Considerations for Patient Retention in Decentralized Clinical Trials, The Association of Clinical Research Professionals, accessed: 06.06.2025 

8. An Examination of the Use of Patient Recruitment and Retention Tactics for Global Studies, Applied Clinical Trial , accessed: 06.06.2025 

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